Amp much quieter after adding speaker out jack

M1dnightrider

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Hi all, got a bit of a problem I could use some advice on. Last summer I acquired an old 1956 supro golden holiday amp; the speakers were nearly toast and the amp rattled like a mother, so I ended up disconnecting the wires from the speakers, soldering extensions, and running them to a jack sitting loose inside the amp. This worked great for months, but being as the amp had a tremolo pedal jack input I never used, I decided to utilize it for the purposes of a speaker in. It worked out after all, but now it seems like I am getting much less output from the amp for some reason.

I did not remove the jack for the tremolo, just moved it out of the way, so I don’t think it has anything to do with that. I did splice and solder a few extension wires onto the leads I had already added so I could still use the original speaker wire (wasn’t long enough to use on its own), is it possible the connections are inadequate and it’s causing loss of input? I also re did the jack connections themselves. I did not use isolating washers between the jack and the amp, would this have any effect?

Any ideas as to what may have happened to cause this are appreciated.
Thanks
 

Dacious

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The trick is reverse what you did and find out why. The existing speaker jack might be insulated. The new repurposed trem switch jack might be grounded - probably is as that's the way most tremolo switches work.
 

radiocaster

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You removed the jack for the tremolo, maybe it is touching something else, like a ground. Maybe it needed to be grounded to the chassis. Don't know, but it's a change.

Also, the amp may need service, Caps, tubes, etc.
 

M1dnightrider

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Ohms taken into consideration yes. I did not remove or alter the trem jack, I used a different one. It was the same one previously used that worked fine, but I did resolder the connections which makes me wonder if it is possible it is losing signal due to inadequate connection.

As for multimeter, what is it exactly I should be checking?

Thanks all
 

M1dnightrider

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You removed the jack for the tremolo, maybe it is touching something else, like a ground. Maybe it needed to be grounded to the chassis. Don't know, but it's a change.

Also, the amp may need service, Caps, tubes, etc.
Hmm that could definitely be possible, I will open up the amp and have a look at where the jack is now situated. Thanks
 

nickmm

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Ohms taken into consideration yes. I did not remove or alter the trem jack, I used a different one. It was the same one previously used that worked fine, but I did resolder the connections which makes me wonder if it is possible it is losing signal due to inadequate connection.

As for multimeter, what is it exactly I should be checking?

Thanks all
Bad grounds (ie:resistance to ground) continuity, dry joints, correct polarity etc.
 

nickmm

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Don't these amps have field coil speakers?
Have you grounded out the output side of the transformer?
 
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2L man

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If volume was normal immediately after the mod you made it is most likely something else?

But if amp was immediately quieter you possibly changed output transformer wires. If amp has 4 and 8 outputs or 8 and 16 outputs you might use now between 4 and 8 or 8 and 16 where voltage is lower and output power only about half?

Bad soldering or corroded jack/plug contact might also cause lower volume but it would be more erratic and end to total failure.

Perhaps non insulated jack can change the NFB somehow or short the signal to chassis so look which wires go to hot and cold from the OT.
 




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